1. Field of the Invention
The present invention relates to a solar cell module to be laid, together with roof tiles, on the tile-base member provided on the roof of a building. The invention also relates to a method of laying solar cell modules and an apparatus for preventing solar cell modules from being blown off.
2. Description of the Related Art
A technique of laying solar cell modules on the roof of a building, together with ordinary roof tiles, is disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 11-200561. The technique is to provide waterproof junction between any solar-cell holding tile, or solar cell module, and the roof tiles.
More specifically, a solar-cell holding tile and a roof tile may be laid, adjacent to each other. In this case, a waterproof anchor having an elastic waterproof member is laid beneath the junction between the solar-cell holding tile and the roof tile. An overlap strip extends from the frame of the solar-cell holding tile, in the direction of the junction. The overlap strip has a hanging part. The hanging part abuts on an edge of the roof tile and remains in resilient contact with the elastic waterproof member of the waterproof anchor. Further, the gap between the roof tile and the hanging part of the overlap strip provided on the solar-cell holding tile is filled with caulking material.
Generally, fastening members that mechanically fasten solar cells to a base member mechanically are screws, bolt and nuts, or rivets. The junction between each solar cell and the base member is made waterproof, by use of caulking material, waterproof seal packing or the like.
The waterproof structure disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-200561 is designed to couple any two adjacent solar-cell holding tiles that are laid side by side. In this structure, the hanging part on the overlapping side abuts on the cell frame on the under-lapping side.
When solar-cell holding tiles are laid on the roof, however, all of them cannot contact at butting edges, due to the uneven surface of the roof and the error in arranging battens on the roof. There may be a gap of about 2 to 3 mm between the butting edges of the solar-cell holding tiles. Rainwater will likely be blown into the gap between the overlapping part of one tile and the under-lapping part of the other tile.
The rainwater thus blown into the gap turns into spray. Here arises a problem. The spray may leak from the sides of the under-lapping part (trough part) onto the tile-base member.
To provide a waterproof junction between any solar-cell holding tile and an adjacent roof tile, a water bar that has an elastic waterproof member may be used, or the gap between the solar-cell holding tile and the roof tile may be filled with caulking material. It is very troublesome to do so, requiring many steps and much time. The solar cells may be mechanically secured to the base member. In this case, it is necessary to render the junction between each solar cell and the base member waterproof, by using a caulking member, waterproof seal packing or the like. This requires many steps of manufacturing the solar cell module, inevitably increasing the manufacturing cost of the module.
Jpn. Pat. Appln. KOKAI Publication No. 11-107453 discloses a cell-holding frame to be laid on a roof-base member. The frame is made of incombustible material, or plate of light metal such as aluminum. Solar cells are fastened to and held in the cell-holding frame. The solar-cell holding frame is as large as a single roof tile, or as large as roof tiles combined together. That is, the solar-cell holding frame is designed on the basis of the shape of a roof tile.
Roof tiles are laid on the roof, spaced from one another at their trough parts, to provide gaps for draining rainwater. Hence, the following problem will arise when a solar-cell holding frame is laid together with roof tiles, if the solar-cell holding frame is one designed in accordance with the shape of a roof tile as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-107453 and has a width that is an integral multiple of the width of a roof tile.
Assume that a solar cell module that has a width equal to the width of n roof tiles combined (where n is an integer greater than 1) is laid together with roof tiles. Then, the roof tiles lie over a distance longer by (n−1) gaps between the n roof tiles. Consequently, the roof tiles are displaced from the solar cell module in staggered fashion. A waterproof member must be used in order to compensate for the displacement.
It will be described how a solar cell module four times as broad as a roof tile, that is, n=4, is laid together with roof tiles.
FIG. 28 shows a comparative example. Numeral 40 designates a roof, and arrow 41 indicates the direction in which rainwater flows. Ordinary tiles 42 and solar cell modules 43 are laid together on the roof 40. Each module 43 is a solar-cell holding frame has a width four times as great as the effective width of one tile 42. Numeral 44 indicates the eaves side, and numeral 45 the ridge side.
First, some tiles 42 are laid on the roof 40, along the eaves side 44 from the right to the left. Then, some other tiles 42 are laid closer to the ridge side 45, in staggered fashion with respect to the tiles 42 first laid, each partly overlapping adjacent two tiles 42 already laid. Having an effective width A that is four times the effective width of the tiles 42, each solar cell module 43 is shorter by a distance equivalent to three gaps and is displaced to the right. Hence, the tiles 42 are staggered to those of the lower row on the right part X of the roof 40, but are gradually displaced toward the left. The tiles 42 cannot be laid in staggered fashion to those of the lower row, on the left part Y of the roof 40.
Tiles 42 are laid first along the eaves of the roof, from the right to the left, forming the first row, as in usual manner. Then, other tiles 42 are laid forming the second row, staggered to the tiles of the first row, each partly overlapping two adjacent tiles of the first row. Since the effective width A of each solar cell module 43 is four times as much as the effective width of one tile 42, the module 43 is shorter by a distance that corresponds to three gaps. Consequently, the module 43 is displaced to the right. Although the tiles are arranged in staggered fashion on the right part (part X) of the roof, the tiles of one row are gradually displaced toward the left. Eventually, the tiles of one row are almost aligned with those of the next row. The tiles cannot be laid in staggered fashion the left part (part Y) of the roof.
This not only results in design disharmony, but also dislocates the trough parts of the tiles. Rainwater may therefore leak.
Jpn. Pat. Appln. KOKAI Publication No. 2000-328747 discloses a technique of preventing tiles and solar cell modules from being blown away by a gust of wind. That is, battens and module-holding plates are secured to the roof panels. Then, solar cell modules and tiles are laid on the battens and fastened to the module-holding plates, such that the tiles have their eaves-side edges overlapping the ridge-side edges of the solar cell modules.
A reinforcing batten is laid on any roof panel that lies adjacent to the ridge side of a solar cell module. The tiles lying adjacent to the ridge side of the solar cell module are secured to the reinforcing batten with nail-shaped fasteners.
Japanese Utility Model Publication No. 3027097 discloses a technique of coupling an elongated metal plate to a batten by using S-shaped clips, in order to prevent tiles from being blown away by a gusty wind. Note that batten holds the eaves-side edges of tiles of one row and the ridge-side edges of tiles of the lower row.
According to Jpn. Pat. Appln. KOKAI Publication No. 2000-328747, the nail-shaped fasteners secure the eaves-side edges of tiles lying adjacent to the ridge side of the solar cell module, to the reinforcing batten. They do not secure the ridge side of the solar cell module at all. The ridge side of the solar cell module may therefore be blown off by a gusty wind.
According to Japanese Utility Model Publication No. 3027097, S-shaped clips couple tiles to one another. It is extremely difficult to use the clips in the case where the tiles are laid on the roof, together with solar cell modules.
An object of the present invention is to provide a solar cell module that can be laid on the roof, together with tiles, without causing any water leakage, and can provide design harmony, and to provide a method of laying solar cell modules of this type.
Another object of the invention is to provide a method of laying solar cell modules on the roof, together with tiles, to fasten the ridge side of each module to the roof easily and firmly so that the modules may be resistant to rainstorms and negative pressures, and to provide an apparatus that prevents solar cell modules from being blow off.